Airborne profiles of NO2, total peroxy nitrates and total alkyl nitrates, analysis of forest fire plumes during BORTAS campaign

"Boreal forest fire emissions impact the concentrations and chemistry of nitrogen oxides species locally and across long distance. During the Quantifying the impact of BOReal forest fires on Tropospheric oxidants over the Atlantic using Aircraft and Satellites (BORTAS) campaign (Canada, summer 2011), were carried out several profiles from ground up to 10 km with the BAe-146 aircraft. In those profiles the concentrations of NO2, total peroxy nitrates (∑PNs, ∑RO2NO2), total alkyl nitrates (∑ANs, ∑RONO2) and other compounds (i.e. CO, O3, VOC) were measured. The analysis of the profiles, selecting those effected by Boreal forest fire emissions (CO > 200ppbv), show an increase of ∑PNs (that include PAN) compared with background profiles (CO < 200 ppbv) from 2 to 10 times at altitude between 2 and 4 km, and 6 times above 5 km. The increase of NO2 ranges from 2 and 3.5 and it is peaked at 6 km where the CO shows the highest increase. ∑ANs concentrations in fire plumes is from 2 to 12 times higher than background plumes, from ground to 5 km, above their concentrations growth is less evident. The increases of NO2 and ∑PNs as function of the altitude are matched by the increases of methanol, a VOC emitted by forest fire. Looking at O3 profiles its concentration increase is peaked at 2 km with a factor of 1.2, whereas at higher altitude is negligible. Here will be show possible reasons of the different impact on nitrogen oxides of the boreal forest fire emissions, their different behavior with altitude and the role of the distance from the emission region."